Fix out-of-bounds read in Method#inspect for unnamed parameters

For parameters without names, accessing the name in array index 1 would
be an out-of-bounds read.

1 files changed, 7 insertions, 3 deletions

diff --git a/proc.c b/proc.c
index ae1068e24f..8f0eb0a898 100644
--- a/proc.c
+++ b/proc.c
@@ -3332,9 +3332,10 @@ method_inspect(VALUE method)
         for (int i = 0; i < RARRAY_LEN(params); i++) {
             pair = RARRAY_AREF(params, i);
             kind = RARRAY_AREF(pair, 0);
-            name = RARRAY_AREF(pair, 1);
-            // FIXME: in tests it turns out that kind, name = [:req] produces name to be false. Why?..
-            if (NIL_P(name) || name == Qfalse) {
+            if (RARRAY_LEN(pair) > 1) {
+                name = RARRAY_AREF(pair, 1);
+            }
+            else {
                 // FIXME: can it be reduced to switch/case?
                 if (kind == req || kind == opt) {
                     name = rb_str_new2("_");
@@ -3348,6 +3349,9 @@ method_inspect(VALUE method)
                 else if (kind == nokey) {
                     name = rb_str_new2("nil");
                 }
+                else {
+                    name = Qnil;
+                }
             }
 
             if (kind == req) {